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Hi Mireia,
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<div class="">There was a typo in my pseudo-code, the value to be used for cfg.pad would of course be 1.</div>
<div class="">Best,</div>
<div class="">JM</div>
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<div class="">On 27 Feb 2020, at 09:29, Schoffelen, J.M. (Jan Mathijs) <<a href="mailto:jan.schoffelen@donders.ru.nl" class="">jan.schoffelen@donders.ru.nl</a>> wrote:</div>
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Hi Mireia,
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<div class="">Indeed the cfg.pad parameter operates on the full epoch length, not on the sliding window length. This is per design, and it is not a bug.</div>
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<div class="">Although I don’t fully understand the deeper reason of why you want to do what you want to do, one way to get there would be to handcraft your own procedure, and create the TFRs in a computationally inefficient for-loop. This would require a lot
of data bookkeeping on your end. </div>
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<div class="">Procedurally:</div>
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<div class="">for k = 1:the-number-of-time-point-onto-which-you-want-to-estimate-your-tfr</div>
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<div class=""> cfg = [];</div>
<div class=""> cfg.latency = timepoint(k)+[-0.25 0.25-1./data.fsample];</div>
<div class=""> tmpdata = ft_selectdata(cfg, data);</div>
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<div class=""> cfg = [];</div>
<div class=""> cfg.pad = 0.5;</div>
<div class=""> cfg.method = ‘mtmfft’;</div>
<div class=""> cfg….</div>
<div class=""> tmpfreq(k) = ft_freqanalysis(cfg, tmpdata);</div>
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<div class="">end</div>
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<div class="">freq = tmpfreq(1);</div>
<div class="">freq.powspctrm = cat( 3-or-4-depending-on-whether-you-did-cfg.keeptrials=‘yes’-previously, tmpfreq.powspctrm);</div>
<div class="">freq.time = timepoint;</div>
<div class="">freq.dimord = (‘rpt_)chan_freq_time’;</div>
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<div class="">Sounds like an overkill to me, though.</div>
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<div class="">Best wishes, and good luck,</div>
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<div class="">Jan-Mathijs</div>
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<div class="">PS: Please feel free to suggest an update to the help-section of the ft_freqanalysis function, to explain better the cfg.pad parameter. We look forward to a PR!</div>
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<div class="">On 24 Feb 2020, at 18:17, TORRALBA CUELLO, MIREIA <<a href="mailto:mireia.torralba@upf.edu" class="">mireia.torralba@upf.edu</a>> wrote:</div>
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<div class="">Hi, <br class="">
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<div class="">I am a Fieldtrip user and I came across this error <br class="">
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<div class="">ft_error('the specified padding is too short');</div>
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<div class="">when calculating power spectrum using this code:</div>
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<div class=""> cfg=[];<br class="">
cfg.method='mtmconvol';<br class="">
cfg.foi=2:1:40;<br class="">
cfg.t_ftimwin=0.5*ones(length(cfg.foi),1);<br class="">
cfg.pad=1;</div>
<div class="">cfg.taper='hanning';<br class="">
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<div class="">fLast=ft_freqanalysis(cfg,dataLast);</div>
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<div class="">As I see it, the padding should work in each of my time windows (0.5 seconds length each) and therefore the error should not appear, but when I inspected which is the segment padded by the function I saw<br class="">
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<div class="">that what is being padded to 1 is the whole segment. I think this is not right, as what I would like is to increase my frequency resolution by padding each of the timewindows where I calculate the spectrum. The problem I have is that I want to
use as a baseline another segment which has 0.5 seconds length, and as the frequency extracted by mtmconvol depends on the length of the segment, I am getting different frequency resolutions for the baseline and the target data.</div>
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<div class="">Can anyone help me?</div>
<div class="">Thanks and best regards.</div>
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<div class="">Mireia<br class="">
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<div style="color:rgb(136,136,136);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)" class="">
Mireia Torralba Cuello</div>
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Multisensory Research Group </div>
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Center for Brain and Cognition, Universitat Pompeu Fabra</div>
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<span lang="en" class="">Address: Edifici Mercè Rodoreda 24.313<span title="Nom, número de despatx
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